\documentclass[12pt]{article}
\title{Davey's Doc}
\date{}
\author{David Nolan}
\begin{document}
\maketitle{}
%\center{This is text centred}  %	use the  % for comments within a latex doc
\section{first section}
hello, this is a latex document...
\subsection{Introduction}
this is a subsection...
\section{second section}
this is the second section....
\subsection{Background}
this is a subsection...
\begin{equation} 
\label{eqn:i}
\sum_{i=1}^n i
\end{equation}
We would like to use the summation laws to simplify the Eqn. ~\ref{eqn:i}
\begin{equation} 
\label{eqn:j}
\sum_{i=1}^n n
\end{equation}
This simplifies to
\begin{equation}
n
\end{equation}

%	Tell latex to ignore following text using {verbatim}
\begin{verbatim}
int main (int argc, char** argv) {

  int intarray[n];

  populateData(intarray, n);

  return 0;
}
\end{verbatim}

%\includegraphics{image.png}

\end{document}